In the past decade, core biopsy has largely replaced fine-needle aspiration for breast tissue evaluation. The latter technique’s inability to distinguish between invasive cancer and in situ cases and a general unease among pathologists not trained in cytopathology (in interpreting cells rather than tissue) are two of the main reasons that FNA has fallen out of favor (Diagnostic Cytopathology online, November 19, 2008).

At the same time, FNA is less costly, less invasive, and produces fewer complications. It’s an easier procedure for patients, and it produces results for clinicians more rapidly. These facts have prompted some cancer centers to continue to rely on FNA, especially in cases where tumors are small and palpable, while recognizing the diagnostic method’s limitations.

“The benefits of FNA are that it is easier for the patient, and it produces less pain and less trauma to the breast. The risk of infection is also higher with core biopsy,” said Britt-Marie Ljung, MD, professor of pathology at the University of California, San Francisco, and codirector of the UCSF division of cytopathology.

“If a cytopathologist or pathologist is present at the biopsy, results from an FNA can be available almost immediately, and certainly the same day as the procedure,” Dr. Ljung said. A core biopsy, however, usually requires at least two days for a definitive diagnosis.

In a multidisciplinary team setting, where results can be immediately communicated to a woman’s healthcare team (oncologist, radiologist, surgeon), an FNA diagnosis can mean that treatment planning begins right away, according to Dr. Ljung, who discussed FNA at the 2008 Breast Imaging and Cancer: Multidisciplinary Approach to Breast Cancer Symposium hosted by UCSF.

Faster treatment planning can help reduce worry for patients and streamline medical care, especially in cases that meet the triple test: Clinical, radiographic, and pathology results are concordant.

“For breast cancer, the benefits of FNA are that it is a fast and reliable method,” said medical oncologist Pamela Munster, MD, an associate professor at UCSF and director of early phase clinical trials. “In some situations, core biopsy is not needed.”

While the accuracy of results from core biopsy and FNA are both operator-dependent, the training and expertise of the clinician performing FNA is of special concern, according to Dr. Ljung. Th e presence of a pathologist or cytopathologist reduces the number of insufficient samples and improves accuracy of results. At UCSF, where cytopathologists are closely involved in FNA diagnosis, the false-negative rate is only 2%, Dr. Ljung said.

However, studies of FNA in other settings have found sensitivities that range from 43.8% to 95%, while specific cities ranged from 89.8% to 100%, according to the Diagnostic Cytopathology article. By contrast, studies have found that sensitivities for core biopsy ranged from 94% to 99%, and specific cities from 99% to 100%.

When is FNA most appropriate? Oncologist Yelena Novik, MD, an assistant professor of medicine at the New York University Cancer Institute, noted that when a woman has a small palpable breast cancer, FNA is an entirely reasonable choice. In these cases, because the tumor is palpable, there’s usually little question of whether it is invasive. “It’s a double win: The patient gets a procedure that’s less painful and less invasive, and the surgeon gets the most important information rapidly,” she said.